1. Field of the Invention
The present invention relates to a method of controlling the operation of a wobble plate type compressor provided with a wobble plate for converting a rotational motion of a rotatable drive plate having a variable angle of inclination to a linear reciprocating motion of pistons. The rotatable drive plate and wobble plate are received in a crankcase chamber of the compressor, and a displacement of the compressor is controlled by changing an angle of inclination of the wobble plate according to a pressure difference between a pressure in the crankcase chamber acting on one side of each piston and suction pressure acting on the other side of each piston.
2. Description of the Related Art
U.S. Pat. No. 4,747,754 to Fujii et al. discloses a variable displacement wobble plate type compressor with a solenoid-operated wobble angle control valve. This control valve is disposed in a passage extending from a crankcase chamber to a discharge chamber of the compressor, and the control valve is opened and closed according to a pressure detection signal from a suction pressure detector, a temperature detection signal from a temperature gauge, etc., to control a pressure level in the crankcase chamber, thus controlling a displacement of the compressor. The compressor is connected to an engine of a vehicle, and when the engine is subjected to a large load upon, for example, acceleration, the displacement of the compressor is reduced to reduce the load on the engine to provide a smooth acceleration and improve the drivability of the vehicle. To this end, the solenoid-operated control valve must be quickly opened to rapidly increase a pressure level in the crankcase chamber and instantaneously reduce the displacement of the compressor.
Nevertheless, if the pressure level in the crankcase chamber that has been increased to quickly reduce the displacement of the compressor is kept as it is during the acceleration of the vehicle, an excessive load may be applied to connections between each compressor piston and a piston rod, between the piston rod and a wobble plate, and between the wobble plate and a rotatable drive plate of the compressor, to damage these connections. If the pressure increase in the crankcase chamber is suppressed to avoid this damage, the displacement of the compressor may not be sufficiently lowered in a short time.